x64 backend: migrate stores, and remainder of loads (I128 case), to ISLE. (#4069)

cranelift/codegen/src/isa/x64/inst.isle

@@ -838,6 +838,11 @@
 (rule (to_amode flags base offset)
       (amode_imm_reg_flags offset (put_in_gpr base) flags))
 
+;; Offsetting an Amode. Used when we need to do consecutive
+;; loads/stores to adjacent addresses.
+(decl amode_offset (Amode u32) Amode)
+(extern constructor amode_offset amode_offset)
+
 ;; Shift kinds.
 
 (type ShiftKind extern
@@ -1404,6 +1409,15 @@
 (rule (x64_pmovzxdq from)
       (xmm_unary_rm_r (SseOpcode.Pmovzxdq) from))
 
+(decl x64_movrm (Type SyntheticAmode Gpr) SideEffectNoResult)
+(rule (x64_movrm ty addr data)
+      (let ((size OperandSize (raw_operand_size_of_type ty)))
+        (SideEffectNoResult.Inst (MInst.MovRM size data addr))))
+
+(decl x64_xmm_movrm (SseOpcode SyntheticAmode Xmm) SideEffectNoResult)
+(rule (x64_xmm_movrm op addr data)
+      (SideEffectNoResult.Inst (MInst.XmmMovRM op data addr)))
+
 ;; Load a constant into an XMM register.
 (decl x64_xmm_load_const (Type VCodeConstant) Xmm)
 (rule (x64_xmm_load_const ty const)